Earth working machine protector

ABSTRACT

A bypass solenoid valve connects the high pressure and low pressure hydraulic line of an earth working machine such as a trencher, backhoe or earth borer. The valve is normally open so that the machine is inoperative. The machine is made operative only if a key operated switch in the solenoid valve circuit is closed; therefore, the device acts to prevent thefts. In addition, if the earth working tool touches a buried pipe, buried cable, or other object to which a detector is attached, a sensitive electronic circuit de-energizes the solenoid valve, thus deactivating the machine to prevent damage to the buried object.

[ Feb. 25, 1975 EARTH WORKING MACHINE PROTECTOR [75] Inventor: Johnny Lee Broyles, McKinney,

Tex.

[73] Assignee: Tripple 1 Products, Inc.,

McKinney, Tex.

22 Filed: Sept.2l, 1973 211 App]. No.: 399,551

[52] US. Cl 214/762, 37/D1G. 1,37/D1G. 19, 214/138 R [51] Int. Cl E02f 9/24 [58] Field of Search 214/762, 7.63, 764; 37/DIG. l, DIG. 19

[56] References Cited UNITED STATES PATENTS 2,243,876 6/1941 Maddox 37/DlG. 19 2,409.397 10/1946 Sheehan.... 37/D1G. 19 3,659,734 5/1972 Fuzzell 214/764 Primary Examiner-Robert J. Spar Assistant Examiner-Ross Weaver Attorney, Agent, or Firm-Wendell Coffee [57] ABSTRACT A bypass solenoid valve connects the high pressure and low pressure hydraulic line of an earth working machine such as a trencher, backhoe or earth borer. The valve is normally open so that the machine is inoperative. The machine is made operative only if a key operated switch in the solenoid valve circuit is closed; therefore, the device acts to prevent thefts.

In addition, if the earth working tool touches a buried pipe, buried cable, or other object to which a detector is attached, a sensitive electronic circuit de-energizes the solenoid valve, thus deactivating the machine to prevent damage to the'buried object.

3 Claims, 3 Drawing Figures PATENTEB 825K135 3.868.085

SHEET 1 0r 2 FIGJ RESERVOIR 24 ICONTROL cmcwr I 5 28 26; J12

1 EARTH WORKING MACHINE PROTECTOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to earth working equipment having hydraulically controlled elements and more particularly to devices to prevent the theft of such equip ment and to prevent such equipment from cutting buried pipes or cables.

2. Description of the Prior Art Before my invention, various pipe or cable locators were well known. They were used to locate the position of underground pipes and one common system generated a 20 cps (cycle per second) alternating electrical signal and applied the signal to the pipe. A detector was used to search for this signal and thus the pipe. Other systems were to attach a wire to the pipe and then check for electrical continuity when a probe or earth working tool touched the pipe.

Also, before my invention, it was known that when an underground pipe was detected by an earth working tool, an alarm could be given or the hydraulic system of an earth working machine could be blocked. By blocked, I mean that a valve in the high pressure line could cut off the high pressure line.

The following are examples of prior art devices known to me before filing this patent application:

Pavlik l,805,4I2 Maust 2,l3l,29l Sheehan et al 2,409,397 Stryker 2,561,!52 E. Smith et al 3,l90,476 Other examples of the prior art are:

Albrecht 2,6l5,969 Winters 2.789.282 Popelier 3,170,579 Stronger, .Ir., et al 3,296,494 Humphreys,1r. 3.4l8,572 Long-Short 3,653,523

Further prior art are HANSENBALG U.S. Pat. No. 3,407,895 and KELLY U.S. Pat. .No. 3,648,282, however, they-appeared not to be concerned with my in vention.

SUMMARY OF THE INVENTION New andUseful Function l have discovered that by bleeding or draining or relieving the pressure in a hydraulic line that I achieve several desirable objectives.

First, it is quite effective as a buried object protector. l.e., it works quite effectively to protect buried telephone lines, buried gas pipes and water pipes, etc., by bleeding the high pressure line if the tool is proximate an obstruction.

Second, it works for safety. Industrial accidents occasionally occur because sometimes the equipment is left with the backhoe raised when the workmen go home for the evening or the weekend. If children come to play around the equipment and they touch a lever, they permit the backhoe to fall, sometimes causing injury.

Third, my system has the additional advantage as an antitheft device.'l.e., normally, this equipment is left unattended for periods of time, making it subject to theft. Thieves of this type equipment are familiar with normal factory installed locks and how to wire around them or otherwise steal the equipment with this type lock. My lock provides additional difficulty because power must be supplied to the valve or the equipment is relaxed. The outriggers and earth working tools are lying on the ground and unless the device is unlocked by its key, thus activating the valve, the equipment cannot be raised so the machine could be moved. If the wires are cut, then this again makes it more difficult to activate the equipment.

OBJECTS OF THIS INVENTION An object of this invention is to protect earth working machines.

Another object is to prevent such machines from cutting cables, being stolen, or inadvertently being left with pressurized hydraulic lines.

Further objects are to achieve the above with equipment that is sturdy, compact, durable, lightweight, simple, safe, efficient, versatile, and reliable, yet inexpensive and easy to manufacture, install, adjust, operate, and maintain.

Other objects are to achieve the above with a method that is versatile, rapid, efficient, and inexpensive, and does not require skilled people to install, adjust, operate, and maintain.

The specific nature of the invention, as well as other objects, uses, and advantages thereof, will clearly appear from the following description and from the accompanying drawing, the different views of which are not necessarily to the same scale.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view of an earth working machine with an embodiment of this invention shown thereon schematically.

FIG. 2 is a schematic representation of the hydraulic system of the machine according to this invention.

FIG. 3 is a schematic representation of the electrical control system according to this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT An earth working machine as used herein includes vehicle 10 with connected earth working tool 12. In the particular embodiment illustrated, the earth working tool 12 is in the form of a backhoe. The earth working tool is connected to the vehicle by movable structures 14 in the form of arms extending from the vehicle 10 v to the backhoe. Hydraulic pump 16 is mounted on the vehicle 10 and driven thereby. The pump is connected by hydraulic hoses 20 and 22 to hydraulic motor 18. The hydraulic motor 18 is in the form of a hydraulic cylinder attached to the movable structure 14 whereby the earth working tool 12 is manipulated to dig the earth, the intended purpose of the machine.

The hydraulic hoses include high pressure line 20 and low pressure line 22. As will be understood by those familiar with the art, the pump 16 pumps the hydraulic fluid from reservoir 24 into the high pressure line 20. The fluid is utilized in the motor 18 and is returned in the low pressure line 22 to the reservoir 24. Those skilled in the art will understand that there are various control valves to control the hydraulic fluid to the motor 18. In fact, there are a plurality of motors 18 to activate different articulation of the structure 14 attached to the tool 12 and, also, to attach to different tools. I.e., one vehicle might well have a frontloading scoop 13 attached to it as well as a backhoe. Traditionally, backhoe machines have outriggers 15 to steady the vehicle 10 while the tool 12 is being used.

Those skilled in the art will understand that the machine as has been described to this point is conventional, well known, and commercially available on the market. Prior art patents teach detecting means provided for detecting that the tool 12 is proximate obstruction 26, such as an underground pipe or cable. These means for detecting may be of various forms, such as described above, either an alternating signal may be placed upon the pipe and in such case, detection can occur before there is actual contact between the tool 12 and the obstruction 26. In other cases, they take the form of direct electrical continuity in which case the tool touches the obstruction 26. As described in MAUST US. Pat. No. 2,131,291, a signal is produced when the tool gets near the obstruction. Therefore, in this application, the term proximate is used to indicate that the tool 12 is close enough to the underground obstruction 26 that it may be detected by those means which are known to the prior art. These means may detect while there is still a distance between the tool 12 and the obstruction 26, or they may detect only upon contact. However, as used herein, the term proximate is used to include actual contact.

To this system which is known, I have included control circuit 28 operating bleed valve 30 by solenoid 32. The valve 30 might also be called a bypass valve or relief valve. The valve 30 is normally open. This means that normally the high pressure line 20 is connected to line 22 back to the reservoir 24. In effect, this inactivates the entire hydraulic system of the machine and there can be no hydraulic operation or lifting of the tool 12 or the outriggers or other items operated by the hydraulic system. Also, there can be no pressure trapped in the various elements because of this bypass or bleed.

When the solenoid 32 is energized, the valve 30 is closed and, therefore, it is possible to have high pressure in the high pressure line so the motor 18 may be operated to manipulate tool 12 by the structure 14.

Electric energy is connected from source of electric energy 34 by main line 36 to the solenoid 32 with the control circuit 28 more particularly seen in FIG. 3. The main line 36 includes fuse 37 for protection of the parts. Also, the main line 36 includes key switch 38. 1f the switch 38 is locked in the open position, there can be no electrical energy transmitted to the solenoid 32 and, therefore, there can be no operation of the tool 12 by the motor 18 in the hydraulic system. lndicator light 40 from the main line 36 to ground line 42 indicates that electrical power is furnished to the control circuit 28. The ground line 42 is, in fact, the frame of the vehicle 10 and, therefore, the tool 12 is part of or electrically connected to the ground line 42.

As illustrated, the solenoid 32 is connected between the main line 36 and the ground line 42 through transistors 44. Therefore, if the key switch 38 is closed and the transistors are conducting, the solenoid 32 will be energized, thereby closing the valve 30 and making the machine operative. However, if the transistors 44 are not connecting, the solenoid 32 will not be energized just the same as though the fuse 37 or the key switch 38 were open.

The main line 36 is connected through resistors 46, rheostat 48 and resistor 50 and fuse 52 to a probe or clamp 54 and thus to the obstruction 26. Therefore if the resistors 46 and 50 and the rheostat 48 were sufficiently low in ohmage, the contact between the tool 10 and the obstruction 26 would in itself provide a sufficiently low resistant circuit from the main line 36 to the ground line 42 to short or inactivate the solenoid 32 so that it was not sufficiently energized to hold the bleed valve 30 closed, thereby protecting the obstruction. However, more important is the non-conducting state of transistors 44. Triac 56 is connected to tap 58 on the rheostat 48. The triac is connected to the center point between high valve resistors 60 and 62. It will be understood by those skilled in the electronics art that when the tool 10 touches or is proximate the obstruction 26, this change of voltage upon the triac 56 will cause it to conduct through normally closed reset switch 64. This, of course, changes the voltage upon the transistors 44 and causes them to become non-conductive and which results in de-energization of the solenoid 32. The sensitivity of the control circuit may be controlled by the setting of the rheostat 48.

After the triac 56 has fired to cause the transistors 44 to be non-conductive, it is necessary to open the circuit by opening the reset switch 64 so the control circuit is again ready to operate after the contact of the tool 12 with the obstruction 26. Again, those skilled in the art will understand that when the reset switch 64 is depressed, this in itself will also energize the solenoid 32 which will close the valve 30; therefore, permitting the equipment to be operated to move the tool 12 away from the obstruction 26. Those skilled in the art will understand the necessity of being able to operate the equipment, otherwise, a great deal of difficulty would be encountered in moving the tool 12 away from the obstruction 26. This could also be achieved by temporarily disconnecting the clamp 54 from the obstruction 26 or by removing the fuse 52. However, to get the triac back in proper operation, the reset button is also desirable.

The embodiment shown and described above is only exemplary. I do not claim to have invented all the parts, elements or steps described. Various modifications can be made in the construction, material, arrangement, and operation, and still be within the scope of my invention. The limits of the invention and the bounds of the patent protection are measured by and defined in the following claims. The restrictive description and drawing of the specific example above do not point out what an infringement of this patent would be, but are to enable the reader to make and use the invention.

1 claim as my invention:

1. In an earth working machine having a. a vehicle, p

b. an earth working tool connected to the vehicle by c. movable structure,

d. a hydraulic pump mounted on the vehicle,

e. hydraulic hoses connecting said pump to at least one f. hydraulic motor attached to the movable structure whereby the earth working tool is manipulated,

g. said hoses including a high pressure line from the pump to the motor, and

h. detecting means for detecting that the tool is proximate an obstruction,

j.'the improved structure comprising:

k. a bleed valve attached to the high pressure line,

m. said valve connecting the high pressure line to a low pressure point,

n. an electric solenoid controllingly attached to said valve,

s. a control circuit,

t. said control circuit being a control means for deenergizing said solenoid responsive to a signal from said detecting means.

3. The invention as defined in claim 2 with an additional limitation of u. said control circuit utilizing solid state electronic 

1. In an earth working machine having a. a vehicle, b. an earth working tool connected to the vehicle by c. movable structure, d. a hydraulic pump mounted on the vehicle, e. hydraulic hoses connecting said pump to at least one f. hydraulic motor attached to the movable structure whereby the earth working tool is manipulated, g. said hoses including a high pressure line from the pump to the motor, and h. detecting means for detecting that the tool is proximate an obstruction, j. the improved structure comprising: k. a bleed valve attached to the high pressure line, m. said valve connecting the high pressure line to a low pressure point, n. an electric solenoid controllingly attached to said valve, o. said valve open unless the solenoid is energized, and p. a key operated switch electrically connected to said solenoid, q. said switch forming means for de-energizing said solenoid responsive to operation of said switch.
 2. The invention as defined in claim 1 with additional limitations of r. a source of electrical energy attached to said solenoid through s. a control circuit, t. said control circuit being a control means for de-energizing said solenoid responsive to a signal from said detecting means.
 3. The invention as defined in claim 2 with an additional limitation of u. said control circuit utilizing solid state electronic elements. 